directly above the damaged wall is the corresponding wall to a bedroom. No damage there. Opening a small hole low on that wall found no damage or visible pipes. Above the second floor is a finished attic. No water there.
There are 2 bathrooms on the second floor, neither directly adjacent to that wall. One bathroom is in line with the cracked wall, but most of the fixtures are near the outside rear wall, and about 10 to 12 feet from the center problem wall. The second bathroom is on the front exterior wall and has no walls adjacent to the center wall.